go-log

README

Log

Everything related to logging for Go applications. The main logger this work is based on is sirupsen/logrus and packages in this repository provides a standardised, best-practices logger.

Contained in here are three main packages:

• Logger ("github.com/usvc/go-log/pkg/logger")
• FluentD Hook ("github.com/usvc/go-log/pkg/hooks/fluentd")
• Constants ("github.com/usvc/go-log/pkg/constants")

If you are viewing this on GitHub, the main repository is at https://gitlab.com/usvc/modules/go/log and this is just a mirror that's easier to reference (http://github.com/usvc/go-log).

---

Usage

Creating a logger

import (
  "github.com/usvc/go-log/pkg/logger"
)

var textLogger = logger.New()
var anoterTextLogger = logger.New("text")
var jsonLogger = logger.New("json")

Creating a logger that streams to a remote FluentD

For the following to work, you'll need a FluentD service reachable at localhost:24224

import (
  "github.com/usvc/go-log/pkg/logger"
  "github.com/usvc/go-log/pkg/hooks/fluentd"
  "github.com/usvc/go-log/pkg/constants"
)

var log = logger.New()
fluentHook := fluentd.NewHook(&fluentd.HookConfig{
  Host:                    constants.DefaultFluentDHost,
  InitializeRetryCount:    10,
  InitializeRetryInterval: time.Second * 1,
  Levels:                  constants.DefaultHookLevels,
  Port:                    constants.DefaultfluentDPort,
  Tag: "tag",
}
log.AddHook(fluentHook)

---

Configuration

Fluent Hook

Key	Example	Description
Host	"fluentd.monitoring.svc.cluster.local"	Host of the FluentD service
Port	24224	Port which the FluentD service is listening on
InitializeRetryCount	10	How many times the logger should attempt a connection with the FluentD service before giving up. To never give up, set this value to -1
InitializeRetryInterval	5 * time.Second	Duration between which initialization attempts should be made to the FluentD service
Levels	[]logrus.Level{}	Sets the levels for which the hook will be activated
Tag	"application"	The tag which will be used as the primary tag for logs sent to FluentD

---

Development Runbook

This section contains notes for working on code in this project/contributing.

Directory structure

The cmd directory contains example usages compilable to actual binaries.

The lib directory contains things that are not intended for export or use by external code.

The pkg directory contains all the exported things.

Starting FluentD

You will need a FluentD service exposed to your local environment at localhost:24224. To get it up, run:

make fluentd

Running the example application

The following runs the example with the most features:

make run

For other example applications, see the Makefile

Testing

To run the tests:

make test

Releasing to GitHub

The GitHub URL for this repository is https://github.com/usvc/go-log. The pipeline is configured to automatically push to this repository. Should the keys need to be regenerated, the .ssh Makefile recipe contains the commands required to generate the keys in a .ssh directory:

make .ssh

Inside the .ssh directory, copy the contents of id_rsa.b64 and paste it as the DEPLOY_KEY CI/CD variable. Then copy the contents of id_rsa.pub and paste that as a deploy key with write access in the GitHub repository.

Continuous integration/delivery (CI/CD) pipeline configuration

The following environment variables should be set in the CI/CD settings under Variables:

Key	Description	Example
DEPLOY_KEY	The base64 encoded private key that corresponds to the repository URL specified in NEXT_REPO	(Output of cat ~/.ssh/id_rsa | base64 -w 0)
NEXT_REPO_HOSTNAME	The hostname of the NEXT_REPO_URL so that the domain's key can be verified	github.com
NEXT_REPO_URL	The SSH clone URL of the repository to push to in the release stage of the pipeline	git@github.com:usvc/go-log.git

---

License

This project is licensed under the MIT license.